z50r-ghost wrote:...Great reading as always guys; the NS50F thread here is the best and is really growing. Thanks for posting your stories, motomec. I remember reading your story about how you would find scooters that had been abandoned by students at the end of the semester. It was years ago that I had stumbled across that post. Keep them coming please!
Count me in for another "R/C head..." I've been really into building Japanese Kyosho, on road, 4 stroke touring cars for the past 10 years. As well, I am a pretty decent electric r/c heli pilot... Lots and lots of practice, and lots of charging lipo batteries...
-j
Keep them coming please!
Well, you asked for it
The end of the mini racing due to injuries coincided my closing the Scooter shop I had owned for 8 years and I was fairly depressed at the time. The price of Japanese scooters, by the early 1990's had risen to the point that nobody was buying them anymore. Fortunately, I had been able to sell my inventory of new and used parts to a couple of guys in Mexico, so I had some money in my pocket and bought a Honda CB900 Interstate and took off on a two year tour around the country[another story]. I had given my NS to a racing buddy and aside having written a few stories over the years, hadn't though about it much.
As I sit here today, reliving some of those memories, some of the details of what motivated me then and how the project progressed are coming back to me.
I had been interested in 2-strokes since high school and my first street bike was a Bridgestone 175cc twin. All I can say about that bike is that it was fast,...when it ran and it is just as well that BS decided to focus on tires. Actually, the story that I had heard was that they didn't have any choice in the matter. The Japanese Big Four, correctly thinking that four marks were enough, gave BS an ultimatum, Start making tires, or else. BS, wisely, agreed.
My first really fast small 2-smoker was a 1973 Yamaha MX100;
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The little Yama-hamer was so fast that it would keep up with the Bultaco 250 my buddies rode. It also had a trait that suprised me greatly the first time it happened. The engine, using a piston-port induction system and having a breaker points ignition, didn't really care which direction the crank was rotating to run. On one of my many unsuccessful attempts at climbing the local "killer" hill, exhausted, I let the bike roll backwards in gear and it started right up running backwards
Needless to say, if I hadn't had my hand on the clutch lever, it would have been an interesting decent.
The late '70's, found me "turning a wrench" in a Yamaha dealership. The service manager was a well known racer and highly skilled tuner. On arriving Tuesday mornings[closed Mondays-old skool shop], there was always a TD or TZ race engine waiting in his area for a "freshening". It was at this point that I became completely obsessed with Yamaha RD350's, the iconic "boy racer" of the '70's and '80's. When I wasn't studying Gordon Jennings The Two Stroke Tuner's Handbook, I was tracing out porting maps by rolling paper and inserting it inside various cylinders, all the time, bugging him about why he did this or that. Perhaps realizing that I wasn't going to away, he took me under his wing and started showing me the how, and more importantly, the why, of how he worked his magic. Some of the racers, taking pity on me I suppose, started giving me their used racing bits and soon I had one very fast "crotch-rocket", running low 13's a the local strip. I delighted in smoking, quite literally, big road bikes at the traffic lights and I searched out noobies on their Ninjas and Katanas[you could always tell 'em, they rode with their butts way back on the seat].
By 1987, my scooter shop had been open a year or two and I was finally making enough money that I didn't have to have Saltines and water for lunch, and I started getting "antsy" for some 2-stroke modd'ing. I don't remember where I had heard of Kitaco, but I contacted them in Japan and started ordering Honda 50cc scooter big-bore kits[possibly, the first used in the US]. I well remember taking the first Aero 50 cyl. to the machinist, only to have him call me a short while later with the news that "he had struck daylight". His code for, he had bored though the liner trying to open the cyl. enough for the kit piston. I was becoming aware of the suttle differences between the US and Home models.
There really wasn't much available in the way of aftermarket performance scooter parts at the time and I was relegated to modifying the O.E.M. pieces. Porting the cyl.s, reshaping the combustion chambers and tightening up the squish band, matching the crankcase transfers, boring out the carb venturi, etc. The obvious choke point was the reed block asm. Attempts at fitting a larger manifold and reed block were thwarted by a lack of material in the crankcase area next to the cyl. Even tried building up more material by successive welding to fit an NH80 reed block but without success.
All this, plus the shiney Kitaco pipe make for a scooter that was.....only slightly slower than the stocker
, at least up to the stocker's top end, at which point it would pull away. For you see, there were no aftermarket Variator or final drive parts at this time. Heck, the term variator hadn't even been coined yet, we called them Salsburys. I had built the equivalent of a 5,500 rpm Sm. Block Chevy that was still running 3.08 gears. But my "angry bee" scooters became a fixture around town and I changed my store logo;
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Around this time, a local YSR club developed and started staging races in parking lots. Even though I knew what the outcome would be, I fitted some reasonably sticky IRC tires to the Aero and striped the plastic off[the floorboard would hit the pavement]and took the Aero 50 out. Got dusted big time.
By now, I was bursting to show up the YSR's, but with what? The AR60 and CR60 were out as they exceeded the 50cc limit[the club probably would have let me race with one of those, but by this time, my pride wouldn't permit it]. So what was left? By default, I became a MB5 racer and it was with the "Meat Ball 5" that I was to continue on the learning curve[read: more failures]til such a time I was really to take on the accursed YSR's.
My time with the MB5 can best be summed up as one long exercise in frustration. It seemed that everything I did to make it go faster, make it go slower. And the wheels and tires were a major problem. But here I was to learn a lesson that would serve me well when I did build a big wheel NS50 racer. To wit, getting some sticky rubber on the ground is not the only important thing with minis, but that keeping the overall mass of the rolling stock down was just as crucial.
In all racing, it's not the speed going though the corners that is important, it's the speed coming out of the corners that is[Keith Code took 100 pages in Twist Of The Wrist to say this]and the bigger and heavier the wheels and tires, the slower the acceleration to speed, more so with minis which need to carry every last oz. of speed out.
The short story-MB5/racing=fail.
So I bit the bullet, bought a YSR and although my heart wasn't in it, I raced with the guys.
And bided my time.
So when news of an updated, liquid-cooled MB5 started tricking in in '89, was became a regular at the Honda dealers and when the NS[stands for-Not Slow] did arrive that fall, I bought the first one.
I was ready to get down to business!
End of part I
To be continued...
Part II-NS50F racing development
